After winning the toss and electing to field, West End Redbacks pace duo Joe Mennie and Kane Richardson made full use of the conditions to leave the Blues staggering at 5/27 with all their specialist batsman back in the pavilion inside seven overs.
Mennie returned 3/39 including three top-order scalps, while Player of the Match Richardson starred with figures of 3/25.
Promising leg-spinner Lloyd Pope (1/48) also snared a late scalp in his one-day debut for the State, much to the delight of his teammates.
A 64-run stand between captain Peter Nevill (40) and allrounder Daniel Sams (35) lifted the Blues’ score late, but NSW could still only muster 173 off 38.4 overs before losing all 10 wickets.
SA's top five all made starts early in the chase with Alex Carey (36), Callum Ferguson (22) and acting skipper Jake Lehmann (37) all making contributions.
Experienced batsman Tom Cooper then posted his second half-century in as many matches to steer the Redbacks home at 5/177.
His mature, unbeaten knock of 52* cemented SA’s first win of the series and lifted the Redbacks into third place on the tournament table behind Western Australia and Queensland.
South Australia host Tasmania at Adelaide’s Karen Rolton Oval on Sunday in the State’s next one-day match.